Packing means for shafts



Jun 16, 1942.

,H. 1:.- LA BOUR PAGKINGMEANS FOR SHAFTS Original Filed Sept. 2, 19:59

2 Shets-Sheet l 1521/82; for:

June' 16,1 942. LA H 2,286,425

PACKINGMEANS FOR- snAFrs original Filed Sept. 2, 19:59 v ZSheets-Sheet 2Patented June 16, 1942 UNITED" STATES PATENT' OFFICE 2 PACKING 30K,SHAFTs Original fzlziiiio fsezz mie t g zii f efiai No.

Divided and this application'March 29, 1841, Serial No. 385,888

9 Claims.

\ the ever present difliculties is to keep the shaft suction within thepump, might not 'be adequate tight against the entrance or exit of airor work- I ing fiuid, asthe case may be. In the case of the centrifugalself-priming pump, tightness of the packing gland or shaftseal is ofvery great practical importance in that leakage of air inwardly,particularly during priming, is destructive of the vacuum which can beattained, and unless provision is made for an adequate shaft seal, theselfpriming -.pumpwill not operate satisfactorily.

While the present shaft seal has been designed particularlyfor meetingthe problem of the selfpriming centrifugal fire pump disclosed .in myparent application, it has general utility, as will appear from thedetailed description and-statement of operation.

In shaft seals employing fibrous packing, it is desirable to maintain acontinuous resilient pres sure upon the fibrous packing to make itconform as nearly as may be possible to the shaft.

8 One of the difliculties of the devices of the prior art is that whenthe gland follower is controlled solely through resilient pressure, asby the application of' springs, the gland follower not infre- 'quentlytends to-cock to one side and thereby distribute the spring pressureunevenly and produce an unsatisfactory seal. According to the presentinvention, spring pressure is applied by a single spring guided in suchrelation to the shaft that no appreciable cocking of the follower Incentrifugal fire pumps, such as herein illushated, the pump may berequired to raise liquid from a lower level, that is, ame'gative head,

in which event the packing is under suction; or the pump may be employedas a booster pump, water under pressure of the order of 50 to 60 mains,through fire hydrants or the like. It can be seen at once that a springpressure adequate to keep the packing tight under conditions of to keepthe packing from being blown out when the pump is subjected to internalpressure of the order above indicated. If, in accordance with the priorart, the spring pressure upon the gland follower should be increased tothe point of being able to hold against the above recited internalpressure, this spring pressure would be excessive under normalconditions where the pump is subjected to suction. Excessive pressure onthe packing is to be avoided because it tends to cause heat withresultant friction and wear, and, in the case of* corrosive chemicals,to accelerate corro-.

sion.

According to the concept of the present invention, a gland follower isengaged by a coil spring surrounding the shaft and compressedbetween thegland follower and a shoulder on a-sleeve surrounding the shaft. Thesleeve carries threads by which it may be positively advanced, first,

to compress the spring and, further, to engage I the gland follower. Thespring, which is preferably pre-stressed to the desired degree, appliesthe desired normal pressure to the gland follower to keep'the packingtight. The sleeve has an extending portion which may be brought intopositive engagement with the gland follower,

first, to apply positive pressure thereto for com- 40 puting the springunder compression, and then engaging the follower positively to drive itagainst the packing. 'After the shaft has operated for a time, and thepacking has worn, the spring with its persistent resilient pressurecauses the follower to take up the wear in the packing and, by movingforwardly, to leave contact with the sleeve. If now the pump should besubjected to internal pressure, tending to drive the packing out of itsrecess, the follower can be driven back no farther than the distance ofthe small gap caused by takeup due towear, and when this gap has beenclosed up between the follower, and'j the head of the sleeve, the sleeveprovides a firm unyielding back stop for the follower, which prepoundsper square inch being derived from water vents any further dis-placementof the packin rotating the sleeve onits threads or other equive alentthreaded means for advancing the sleeve and thereb bringing the sleeveinto engagement with the follower. I The object of the present inventionis to provide a simple, effective, and conveniently serviceable 'form'of shaft seal for centrifugal pumps and the like generally, and forself-priming centrifugal pumps specifically. I

A further object is to provide a shaft seal which is effective over awide range of fluid pressures,

positive and negative, without requiring abnormal spring pressure on thefollower.

Now in order to acquaint those skilled in'the art with the manner ofconstructing and operating my invention, I shall describe, inconjunction with the accompanying drawings forming a part of thespecification, a specific embodiment of the manner of constructing andoperating the same.

In the drawings:

Figure 1 is a side elevational view, partly in a gasoline engine drivingmotor directly connected and employing the seal of my invention;

Figure 2 is a vertical section, longitudinally of the shaft, showing theshaft seal of Figure 1; Figure 2A is a fragmentary section of the springbarrel or s eeve with the auxiliary follower held by a pin to preventexpansion of the follower spring; and

Figure 3 is a view similar to Figure 2, illustrating the use of atwo-part shaft in this conv struction.

Referring to Figure 1, the driving motor I is preferably a small,high-speed, four-cylinder gasoline engine having the usual operatingparts including a crank case 2 -and a flywheel housing 3 in which thereis disposed the engine fiy wheel 4 mounted on the crankshaft (notshown), the

crank shaft having/suitable hearings, in the en gine frame, as is old inthe art. The self-priming centrifugal pump 5 .comprises an intake trap6, an impeller housing I, and a separator 8. The impeller 9 is disposedin the impeller housing between the back plate In of the main frameelement I! of the pump housing and a front plate member I 3. The frontplate member i3 has a short tubular intake connection l4 whichcommunicates with the interior of trap 9. The trap, ,6 has a boltingflange I! which engages the offsetclamping flange IE on the front platel3. By means of bolts 11, II the flange I 5 of the intake trap member Iis clamped against the flange It, the member l9 having a slightlytapered annular shbulder which'is forced within the confines of thecorrespondingly tapered inner periphery of the bore of main frame memberl2, and theseparts being firmly held together on suitable pilots.

The intake trap 9 has a threaded inlet l9 for communication with asuitable suction pipe main and auxiliarylports therein providingcommunication between the channel in which the imp ller 9 runs and theinterior of the separator 3, the separator having a flange 23 matingwith the flange 24 on the pump body I2, whereby these parts are clampedtogether. The pump is of the hydraulic balance type disclosed in myPatent No. 1,578,236.

The separator at its upper end has an air vent connection leading to asmall copper tube 28 permitting'the escapeof air while the fire pump isfilling its suction with the discharge shut ofl, as is explained inconnection with the parent case. This vent is preferably of theconstantly open type. A discharge opening 23 in the top of the separator3 is adapted to be connected to the flre hose or other discharge conduitthrough a shutofl' valve. A pressure gauge 21 is connected to theinterior of the separator as through the pipe 28 to indicate when thepump has filled its'suction pipe and is ready to throw water out throughthe fire hose.

The pump 5 and motor I are connected together by a bell bracket 29 whichhas a flange 39 mating with the flange 32 on the flywheel housing 3, thetwo parts being piloted together and held by the cap' screws 33. Themain pump body l2 has a short neck 34 terminating in a flange g5 35 uponwhich is piloted the bell bracket 29 and section, of, a self-primingcentrifugal pump with a to which the bell bracket isclamped by means ofthe inwardly extending flange or series of lugs'36 and studs 31. Thesides of the bell bracket 29 .are provided with openings or windows 8039 through which the studs 31 may be drawn 85 hub member 39 whichcooperates .with the threaded sleeve 40. Referring more particularly toFigure 2, it will be seen that the sleeve 49 is mounted on threads inthe hub or plate 39 of the bell bracket, and this sleeve has a flange orhead 40 42 with capstan sockets 43 which may receive a suitable pin orspanner wrench for rotating the sleeve on the threads.

Obviously, as an alternative mounting, the

sleeve 40 may be mounted non-rotatively in the 45 plate or hub 39 andprovided with a nut for forcing the said sleeve towards the left whenthat is desired.

-The.' back plate III of the pump body I2 has a central opening throughwhich extends the im- 60 peller shaft 44. In the construction shown inFigures 1 and 2. the impeller shaft is welded at its right hand end to aplate 45 which in turn is bolted to the flywheel 4 of the engine. Theimpeller 9 is removably mounted as by means of a key and nut or othersuitable construction-upon the end of the shaft,whereby it may readilybe removed without requiring removal of'the shaft if the pump and motorare to be separated or if the impeller is to be replaced. A shaft 44extends through themes or hub 48 of the back plate It, this hub havingan annular recess or counterbore'" in which there is disposed thefibrous packing 43. for making a tight Joint between the shaft and thepump body. ,A gland g5 follower 49 of known formhaving at its reduced 2end a slightly concave face engaging the fibrous packing 49 is enteredinto the counterbore so as to securea guidance or piloting therein, andis adapted to be forced against said fibrous pack- 7 ing 43 to maintainthe seal. The rear end of the follower is enlarged in diameter andcontains an annular recess orcounterbore in which aaaaacc distributingrecess 54 which is connected exgroove 59. In that position a slightforward ternally as by a small diameter pipe 55 to a compression greasecup 59 or the like. The auxiliary packing 52 and its follower areintended to maintaina tight seal at the rear of the lubricating chamber54, so that when lubricant under pressureis forced into the chamber 54,it may be driven forward between the shaft and the packing 49. Theauxiliary follower 53 is preferably piloted in the counterbore 59 but atall events is guided'in'the bore of the sleeve 49, so that it tends tobe maintained in correct alignment with the axis of the shaft. A coiledcompression spring 51 is disposed between the auxiliary ,follower 53'and the inwardly extending flange 59 on the rear of the said sleeve.This spring is disprojection of the follower 53 permits it to applypressure to the said packing 52 in excess of that which the spring 5!alone could apply.

' Assuming that the parts are in the position shown in Figure 2, andthat some wear on'the packing 49 has occurred and has been taken up byrecoil of the spring 51, the-follower 49 and posed in the pocket thusformed under initial,

stress. In other words it is prestressed, and if released would expandbeyond the end of the sieeve. The follower 49 has on its right hand end,as viewed in the drawings, a flat annular engaging face for engagementby the head 42 of the sleeve 49. The head 42 of the sleeve has a likeflat annular engaging face, and these faces are at right angles to theaxes of the shaft so .that this engagement tends to true up the posieverthe sleeve 49 has been advanced on the threads to engage the saidfollower 49. Whenwear occurs in the packing 48, the volume thereof isreduced and the follower 54 under the influence of the spring 51 movesto the left and takes up the volumetric loss, the packing actingsomewhat as a stiff fluid permitting deformation and displacement underthe pressure of the spring Obviously, the auxiliary packing-52 andauxiliary follower 53 constitute a refinement which,

while not absolutely necessary in some cases, is

generally desirable. The spring thus" exerts its pressure of recoil uponboth packings 52 and 49 in series and keeps them both displaced intocontact with the shaft 44.

When wear of a predetermined amount has' openings 43 and extending thesame into the groove 59, the spring may be held under-compression, .sothat it cannot force the follower 53 out beyond the sleeve except insmall degree,

"and thereupon the sleeve 49, the auxiliary follower 53 and the spring59 may be moved as a unit to the right by turning on the threads,

I thus providing the necessary space for servicing the head 42 of 'thesleeve will be out of engagement, since the spring will have thrust themain follower 49 to the left to make up for the loss of volume'of thepacking 49. The follower 49 is free to slide back and forth, although itis prevented from turning by the pipe 55 which extends through a slot inthe bell crank 29 as shown in Figure 1. Normallythe pump in operationisunder suction since it lifts liquid from the level below the pump. If,however, the pump should be connected with the intake connection l9supplied, with water under pressure as would be the case if the pumpwere connected to a fire hydrant, the packing 49 would be under thepressure prevailing in the impeller chamber. The usual water hydrant incity water supply systems carries a pressure of the order of 55 to 60pounds, and it may 'be higher. The tendency is to force the packing 49out of the recess 41, bu this is prevented in the present construction bthe follower 49 coming into engagement with the head of the sleeve 44 assoon as the gap, due to wear, is taken up. Thus the packing will be kepttight against a high internal pressure, as well as against internalsuction without requiring a spring pressure greater than hearings.

that which is sufficient to keep the packing tight under suction.

In Figure 3 I have illustrated the sleeve 49 gap, such as would beoccasioned by wear on the main packing 48. In this figure I haveillustrated also the use-of a unitary impeller 9 and impeller shaft 9a,such as would bedesirable for handling corrosive liquids. The impellershaft 911 is joined to the shaft 44a which is mounted either in suitablebearings in, a stationary part of the installation or connected to anextension which is mounted in suitable The impeller shaft 9a iscounterbored to receive the stud portion 69 of the shaft 44'. The

shaft 44' and its stud or reduced diameter portion 90 may be made of ametal which'is not either the packing 52 or the packing 49 or both ofthem.

Obviously, also if it is desired to apply the positive pressure of thethreads first to the-packing 52, this may be accomplished by pinningtogether the sleeve 40 and the follower 53 through the medium of a pinor pins 4| in one or more of the sockets 43 extending into the 79 ofshaft seal-a member such as-the plug or plate is disposed is closed by atapered plug 65 The corrosion resistant stud 99, and the said telescopicparts being providedwith a suitable key 62. A central bolt, 93, the headof which is recessed in a counterbore formed at the left end of theshaft 9a, draws the two telescoping parts together,.and the recess inwhich the head -94 of the bolt 93 provides a fluid-tight closure.

The operation of theform shown in Figure 3 is otherwise identical withthat shown in Figures 1 and 2.

' The unit as a whole is supported on a frame as by the pads on themotor frame and" 91 on the pump,/so that the parts are adequatelysupported, and the two units are kept in alignment by the bell bracket29. The formof this bracket may obviously be varied, and a differentform of connection' between the units maybe provided; There is requiredfor the present type which those skilled in the art.

from the invention as defined in the appended vgaging said auxiliarypacking, a threaded sleeve adapted to embrace the shaft and to beadvanced auxiliary follower being guided in said sleeve,

39 rigid with the frame of the pump, so that the sleeve 40 may have apositive support against which it may react both for supplying thespring pressure and for providing the positive pressure or back stopeffect, as the case may be. Obviously, the shaft instead of beingmounted as an extension of the crank shaft, may be supported in asuitable bearing independently of the drive of the motor, as will beapparent to The head "is adapted for operation by a spanner wrench or asmall rod inserted in the opening 43, but obviously this head may beshaped in any suitable manner for engagement by a wrench or other meansfor rotating the sleeve.

I do not intend to be limited to the specific details herein disclosedas they may be varied within the skill of the art without departureclaims.

I claim:

1. Packing means for a shaft comprising in combination an aperturedpressure containing member, a shaft extending through the aperture, saidmember having an annular recess for packing surrounding said aperture, asupporting bracket rigid with said member, said brack'et having a ringmember surrounding said shaft and spaced from said member to provideroom to service the packing, said ring carrying inter-. nal threads,packing in said recess, a gland follower engaging the packing, a coilspring on the shaft transmitting its recoil to the follower and a sleevethreaded in the ring and having an internal shoulder for engaging therear end of the spring to compress the same, said sleeve having ashoulder head at its forward end by which the sleeve may be turned onthe threads, said head forming a solid annular abutment for engaging thefollower.

2. The combination of claim 1 wherein the follower has a lubricatingrecess with 'a lubricant with the sleeve.

3. Packing means for a shaft comprising a gland follower adapted toembrace the shaft and to compress a suitable packing thereupon, saidfollower having an annular. recess for receiving auxiliary packing, anauxiliary follower for eninto engagement with the first follower,-saidsleeve having an. annular space for-receiving a compression, spring, aspring in said space, the

said sleeve having a head by which the sleeve may be rotated on itsthreads, and means for holding the auxiliary follower in the sleeve toprevent expansion of the spring when the sleeve is moved endwise awayfrom. the follower.

annular recess for auxiliary packing, an auxiliary follower for engagingthe packing in said 70 recess, a threaded sleeve adapted to embrace theshaft and having a flange at its rear end, a spring.

the 'said flang said I follower, the sleeve having'a head by which it 5openings.

ing openings and the auxiliary follower having a shoulder by which thehead of the sleeve andthe auxiliary follower may be coupled together bythe insertion of a pin through one of- 5. For use in a direct driv'enmotor pumpunit wherein the pump has a back plate and the motor has aflywheel housing, the combination of a bell bracket having a. frontflange adapted to be bolted to the back plate and a rear flange adaptedto be bolted to the flywheel housing, a hub in the rear of the bellbracket, the hub having an opening for the passage of a shaft, acup-shaped sleeve seated in and supported by the hub and having screwthreads upon which it may be advanced and retracted axially along theshaft the sleeve, and a gland follower adapted to receive the thrust -ofthe spring to take up packing wear, the follower and the head of thesleeve being adapted to be positively engaged independently of thespring.

6. In combination, -a pump body having a shaft opening and acommunicating packing recess, a rotatable shaft extending through saidopening, packing in the recess, a follower having "a'portion of reduceddiameter adapted to enter said .recess to compress the packing up on theshaft and having an enlarged head portion, a bracket rigid with thepump'body having a ring member axially in line with said shaft openingand surrounding said shaft, said ring being spaced from said pump body,a spring barrel surrounding the shaft and having an enl-argedhead at theend adjacent the follower and being threaded at its other end externallyinto the said ring, said head being adapted to engage the head portionof the follower to compress the packing,

a coiled compression spring disposed in the spring barrel and engaging ashoulder in the barrel, the other end of the spring reacting against thefollower to keep the packing compressed, said spring barrel beingmovable axially on said threads away from the recess far enough topermit the follower to move away from the recess to give access to themouth of the recess for servicing said packing.

7. In a packing gland construction, a member having an openingcounterbored to provide a packing recess, a shaft to be packed extendingthrough said opening, packing in the recess, a followeron the shaftextending into said recess and engaging the packing, said followerhaving a packing recess at its outer end, secondary packing in saidsecond recess, means comprising a duct opening into the interior of saidfollower for introducing a lubricant between said packings, an auxiliaryfollower on the shaft for'entering the second recess and compressingsaid secondary packing, a bracket rigid with said member carrying a ringsurrounding said shaft, said ring being internally threaded, a springbarrel externally threaded at its'outer end to thread into said ring, acompression spring in said barrel, an internal shoulder in said barrelforming an abutment for said spring, said springbeing compressed betweensaid auxiliary follower and said abutment, said barrel having at itsinner end a head adapted to be engaged by a tool for tuming the barrelon its threads, said head being engageable with the first-named followerto force itaxially against said first named packing.

'may be turned upon the threads, said head hav- 'le 8. The combinationof claim 7 wherein said barrel and auxiliary follower have means forrestraining the expansion'of the spring when the barrel is retractedfrom the main follower to permit servicing of the packing.

9. In combination, a pressure container havcess far enough to permit thesleeve and the follower to be withdrawn away from the recess to giveaccess to the recess, the enlarged rear portion of the follower having acounterbore forming an auxiliary packing recess, an auxiliary followertelescoping with the adjacent end of the sleeve and being adapted toenter the auxiliary recess to compress the auxiliary packing, acompression spring carried in said sleeve and engaging the auxiliaryfollower, said sleeve having a head at its front end for reaching overthe auxiliary follower and positively engaging the enlarged rear portionof the first follower and aligning it with the axis of the shaft.

i HARRY E. LA BOUR.

